JP3423172B2 - Electric refrigerator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control cabinet such as an electric refrigerator for general household use and business use, and more particularly to a food preservation which requires temperature control using a Peltier device. About the warehouse. 2. Description of the Related Art A conventional electric refrigerator uses a refrigerant of a Freon type to utilize the latent heat of vaporization to maintain the inside of the refrigerator at a low temperature. However, destruction of the ozone layer by Freon is regarded as a problem. Research and development of a refrigerator, a freezer, a cooler, etc. using a Peltier element as a cooling system replacing the refrigerant system have been actively conducted. [0003] This type of cooling system using a Peltier element has no environmental destruction because it does not use chlorofluorocarbon gas, has excellent cooling performance, has no fear of gas leakage, and has no vibration or noise because it does not use a compressor. Since the main component is a semiconductor, it has excellent features such as long life and miniaturization. FIG. 13 shows temperature control of a compressor type refrigerator (set temperature in a refrigerator + 2.5 ° C. curve X) and temperature control of a refrigerator using a Peltier element (set temperature in a refrigerator−0.2 ° C.).
It is a figure showing the characteristic pattern of curve Y). [0005] As is apparent from this figure, the compressor-type refrigerator takes a considerable time from the start of temperature control until it reaches the set temperature, during which time the temperature in the refrigerator fluctuates greatly up and down. In contrast, refrigerators using a Peltier element start temperature control and reach a set temperature within a short time, after which the temperature inside the refrigerator is kept almost constant, and the temperature is lower than that of a compressor refrigerator. The control accuracy is very good, and it has the feature that the set internal temperature can be accurately maintained. In designing a refrigerator using a conventional Peltier device, the ambient temperature, the set temperature in the refrigerator, the inside dimensions of the refrigerator, the thermal conductivity of the heat insulating material, the thickness of the heat insulating material, the Peltier device 1
Based on the amount of heat absorbed by each unit, the required amount of heat absorbed as a refrigerator was calculated based on the temperature difference determined from the set temperature in the refrigerator and the ambient temperature, and the number of Peltier devices to be installed was determined accordingly (""Overview of Thermoelectric Conversion System Technology" Section 4 Refrigeration
Izumi, ”pp. 87-88, published by Realize. [0007] In designing a refrigerator using a conventional Peltier element, the above-described procedure was taken. However, the temperature inside the refrigerator generated when the heat insulating door of the refrigerator was opened and closed. No consideration is given as to how long the rise will take, and the amount of power input will be low to reduce economically. [0008] Therefore, it takes time to cool down to the set temperature in the refrigerator after opening and closing the heat-insulating door, resulting in deterioration of the quality of foodstuffs stored in the refrigerator, or conversely, the input power becomes more than necessary. There are various problems such as high running cost and uneconomical. SUMMARY OF THE INVENTION It is an object of the present invention to provide an electric refrigerator which can solve the above-mentioned drawbacks of the prior art and can cool down to a set temperature economically in a short time even if an insulated door is opened and closed. . [0010] In order to achieve the above object, the present invention provides a casing formed of a heat insulating layer, a heat insulating door for opening and closing an opening of the casing, and a heat insulating door installed in the casing. A heat conductor having a heat transfer surface facing the internal space in the casing, a Peltier element thermally conductive with the heat conductor, and an element power supply unit for supplying power to the Peltier element, Within 12 minutes after opening and closing the insulated door
To cool until the internal set temperature, 1.3 to 2-fold with closed <br/> insulating door at the outside air 30 ° C. for the required steady state power for maintaining the internal temperature setting of the casing The electric power regulated to the range described above is supplied from the element power supply section to the Peltier element. DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, according to the present invention, the steady-state power required to maintain a set temperature in a refrigerator with the heat-insulating door closed is 1.3 to 2 times the steady-state power. Regulated power,
The Peltier device is configured to be supplied from the device power supply unit. In this way, as described later, even if the heat-insulating door is opened and closed, it can be economically cooled to the set temperature in a short time. FIG. 3 is a temperature characteristic diagram showing a set temperature in the refrigerator and a temperature change when the door is opened and closed when a Peltier element is mounted on a refrigerator having a capacity of 75 liters. The temperature set in the refrigerator is 3.0 ° C., and the input power at that time is 48 W. Note that, in the specification of the present invention, the input power to the Peltier element required to maintain the temperature in the refrigerator at the set temperature in the refrigerator without opening and closing the heat insulating door at 30 ° C. in the outside air is defined as steady power. In this case, the input power of 48 W corresponds to the steady power. As is apparent from FIG.
Before the heat-insulating door is opened (at the time), the temperature in the refrigerator is accurately maintained at the preset temperature of 3.0 ° C., but the heat-insulating door is opened (at the time). The temperature inside rises sharply. When the heat-insulating door is closed 10 seconds later, the temperature inside the refrigerator drops, but the input power is 48 W, so the gradient of the temperature drop becomes very gentle after about 5 minutes and even after 60 minutes (at the time). Does not reach the internal setting temperature of 3.0 ° C. When the refrigerator is driven with the steady power as described above, even if the Peltier element is used, it is not possible to sufficiently cope with a sudden rise in the internal temperature due to the opening and closing of the heat insulating door, and the internal temperature reaches the set internal temperature. It takes a long time to cool, and during that time, there is a concern that foods stored in the refrigerator may be adversely affected. FIG. 1 shows that the input power is 60W, 70W, 12W.
FIG. 9 is a characteristic diagram showing a temperature change when the heat insulating door is opened and closed under the same conditions as described above except that 0 W and 200 W are set. As described above, since the steady power is 48 W, the input power 60 W is 1.25 times the steady power, the input power 70 W is about 1.5 times, the input power 120 W is 2.5 times, and the input power 200 W is about 4. 2
Equivalent to double. As is apparent from FIG.
In the case of 0 W, the temperature in the refrigerator does not drop to the preset temperature in the refrigerator until 15 minutes or more have passed since the opening and closing of the heat insulating door, and the Japanese Industrial Standards for refrigerators (J
(IS C9607) (cooling to the set temperature in the refrigerator within 12 minutes after opening and closing the heat insulating door) cannot be satisfied. On the other hand, by setting the input power to 70 W, after opening and closing the heat-insulating door, it can be cooled to the set temperature in the refrigerator within 12 minutes, and the input power is further reduced to 120 W and 200 W.
With the increase, it is possible to quickly reach the in-chamber set temperature. FIG. 2 shows that the set temperature in the refrigerator is -1 ° C. (chilled temperature range), the steady power is 70 W, the input power is 90 W,
FIG. 10 is a characteristic diagram showing a temperature change when the heat insulating door is opened and closed under the same conditions as described above except that the temperature is set to 05 W and 120 W. In this case, the steady power is 70 W, so that the input power 90 W is 1.3 times the steady power, the input power 105 W is 1.5 times, and the input power 120 W is about 1.7 times. As is clear from FIG. 1 and FIG. 2, the input power is set to be 1.3 times or more of the steady power even when the set temperature in the refrigerator is changed. Can be cooled down to the set temperature in the refrigerator within a short time that has almost no adverse effect on the quality of the product. FIG. 4 is a diagram showing the relationship between the current flowing through the Peltier element, the amount of heat absorbed by the Peltier element, and the COP. As is clear from this figure, when the temperature difference is constant, the amount of heat absorbed by the Peltier element increases as the current is increased. At a certain current value, the amount of heat absorption becomes maximum (Qmax), and therefore, the COP also becomes maximum. When the current is further increased, the amount of heat absorption (COP) decreases on the contrary. In the specification of the present invention, a current value flowing to the Peltier element when the maximum heat absorption Qmax is obtained is defined as a maximum current value Imax. FIG. 5 is a characteristic diagram showing the relationship between the electric power supplied to the Peltier element and the lowest temperature reached in the refrigerator. Here, the Imax of the Peltier element is 400 W, and the lowest temperature reached in the refrigerator has already reached a plateau at around 270 W. That is, the lowest temperature reached in the refrigerator is almost reached with input power (around 270 W in this experimental example) far less than the operating condition of Imax (400 W in this experimental example), and input of more power is useless. I understand. According to another experiment, the set temperature in the refrigerator was -7 ° C and the steady power was 1
At 30 W, it has been confirmed that 240 W of electric power should be supplied to cool to the in-compartment set temperature within 12 minutes after opening and closing the adiabatic door. In this case, the supplied power / stationary power is 240/130. = 1.8. FIG. 6 is a characteristic diagram showing the relationship between the input power / steady power and the return time to the set temperature in the refrigerator after opening and closing the adiabatic door when the set temperature in the refrigerator and the steady power are respectively changed.
Curve A in the figure indicates that the set temperature in the refrigerator is + 3 ° C. and the steady power is 48.
W and curve B show that the set temperature in the refrigerator is -1 ° C and the steady power is 70.
W and curve C show that the set temperature in the refrigerator is -4.7 ° C and the steady power is 1
00W, Curve D shows that the set temperature in the refrigerator is -7 ° C and the steady power is 1
An experimental example of 30 W is shown. As is apparent from this figure, even under each condition, the input power / steady power must be at least 1.3 times in order to cool to the set temperature in the refrigerator within 12 minutes after opening and closing the heat insulating door. However, even if the input power is increased too much, the return time is not shortened much, and if the return time is within 12 minutes, it does not substantially affect the quality of the foodstuff, and increasing the input power rather increases the running cost. Since it is uneconomical, it is necessary to keep the input power / stationary power within two. Therefore, in the present invention, the input power /
The steady power is regulated in the range of 1.3 to 2. Next, a specific structure of the refrigerator according to the present invention will be described with reference to the drawings. 7 is a front view of the combination device, FIG. 8 is a plan view of the combination device, FIG. 9 is a cut-away side view of the combination device, and FIG. 10 is a plan view of a refrigeration storage room and an ice greenhouse that constitute a part of the combination device. FIG. 11 is a partially enlarged perspective view of a cable storage case used in the combination device, and FIG. 12 is an enlarged sectional view of a heat transfer medium circulation jacket used in the combination device. The combination apparatus according to this embodiment includes a quick freezing room 1, a thawing room 2, a refrigerated storage room 3, and an ice temperature room 4.
And each of the chambers 1 to 4 is independent and individually temperature-controlled. Each of the rooms 1 to 4 has 2 inside the cooking table 5.
It is a stationary type that is integrated into a single layer. The quick freezing room 1 and the thawing room 2 are of a drawer type with respect to a table 5 for easy cooking, and the refrigerated storage room 3 and the ice temperature room 4 are incorporated in the table 5. The quick freezing chamber 1 (thawing chamber 2) has a box-shaped heat insulating casing 6 opened upward as shown in FIG.
It has a heat-insulating lid 7 for opening and closing its opening, and a handle 8 for opening and closing is attached to the left and right ends of the heat-insulating lid 7. A drawer handle 9 is provided on the front surface of the heat insulating casing 6. As shown in FIG. 9, a box-shaped first box made of, for example, aluminum is provided inside the heat insulating casing 6.
A heat conductor 10 is provided, and a cascade Peltier element 12 is adhered to a bottom back surface thereof through a plurality of block-shaped second heat conductors 11 made of, for example, aluminum, and a heat transfer medium circulation jacket 13 is provided outside the cascade Peltier element. Are joined. The power supply cord 14 connected to the cascade Peltier element 12 and the hose 15 connected to the circulation jacket 13 are housed in a bendable elongated cable housing case 16 (see FIG. 11) and are provided on the second heat radiating section 17 side. They are connected (see FIGS. 8 and 9). Therefore, as shown in FIG.
The cable storage case 16 extends when the freezer compartment 1 is pulled out of the freezer compartment 1, and when the freezer compartment 1 is pushed in, the cable storage case 16 bends behind the freezer compartment 1 as shown by a two-dot chain line. Note that the power supply cord 14 is connected to a refrigeration power supply controller 18 installed near the second heat radiating unit 17. In the case of this embodiment, since the freezing room 1 and the thawing room 2 have smaller capacities than the refrigerated storage room 3 and the ice temperature room 4, the hoses 15 of the two rooms 1 and 2 are connected to one second radiator 17. Connected, but with a separate power supply controller.
The power supply cord 14 connected to the thawing chamber 2 is connected to a refrigeration power supply controller 18 and the power supply cord 14 connected to the thawing chamber 2 is connected to a thawing power supply controller (not shown). FIG. 12 shows a heat transfer medium circulation jacket 13.
It is a figure which shows the detailed structure of the vicinity. The circulation jacket 13 has a plate-like heat exchange base 21 joined to the heat radiation side of the Peltier element 12, and the second heat conductor 1
The first frame 22 extends toward one side. The first frame 22 has a hollow shape with an open top and a bottom, and has a base end 23 and an extending portion 24 extending upward from the base end 23, and has a substantially stepped cross section. are doing. The base end portion 23 is liquid-tightly joined to a peripheral portion of the upper surface of the heat exchange base 21 by, for example, an adhesive or a combination of an O-ring and an adhesive. As shown in the figure, the extending portion 24 faces substantially in parallel with the peripheral surface of the second heat conductor 11, and an adhesive 25 is injected between the two to form the second heat conductor 11 and the second heat conductor 11. 1 frame 22
Are joined together. A plurality of positioning pins 82 are inserted between the peripheral surface of the second heat conductor 11 and the extending portion 24, and the adhesive 2
The second heat conductor 11 and the first frame 22 before the complete curing of
Are prevented from being displaced relative to each other. A plurality of (four in the present embodiment) reinforcing ribs 27 extending toward the base end 23 are provided outside the extending portion 24 to maintain the rigidity of the first frame 22. The first frame 22 is formed by making the space between the base end 23 and the extending portion 24 step-like, that is, non-linear.
The creepage distance from the second heat conductor 11 to the heat exchange base 21 is long, and the return of heat transmitted through the first frame 22 is reduced. At the periphery of the lower surface of the heat exchange base 21, a hollow second frame 28 substantially closed at the bottom and open at the top is bonded in a liquid-tight manner via an O-ring 29. A water supply pipe section 30 is provided substantially at the center of the second frame 28, and a drain pipe section 31 is provided near the periphery. The dispersion member 32 installed in the hollow portion of the second frame 28 includes a peripheral wall 33, an upper wall 34 connected to the upper end of the peripheral wall 33, and a large number of members extending from the upper wall 34 to the heat exchange base 21 side. And the nozzle portion 35 is provided.
6 are formed. By fixing the dispersion member 32 in the second frame 28, a flat first space 37 is formed on the water supply pipe 30 side of the dispersion member 32, and the heat exchange base 2 of the dispersion member 32 is formed.
A flat second space 38 is formed on one side, and a drain passage 39 that connects the second space 38 and the drain pipe portion 31 is formed. As shown in FIG. 3, when a heat transfer medium 40 (pure water is used in this embodiment) made of pure water or antifreeze is supplied from the central water supply pipe section 30, it spreads all at once in the first space section 37, Each nozzle portion 35 (injection hole 36) squirts in a substantially vertical direction toward the lower surface of the heat exchange base 21. The heat transfer medium 40 colliding with the heat exchange base 21 and removing the heat thereof quickly diffuses in the second space 38 having a narrow gap,
The water is discharged from the drain pipe section 31 to the outside of the system via the drain passage 39.
The discharged heat transfer medium 40 is connected to the hose 15 shown in FIG.
, Is forcibly air-cooled by a radiator (not shown) provided in the second heat radiating section 17 shown in FIG. 9, and is again sent to the circulation jacket 13 side by a pump (not shown). FIG.
Reference numeral 41 in 2 denotes a heat insulating material layer filled around the heat transfer medium circulation jacket 13. The refrigerated storage room 3 (ice temperature room 4) has a box-shaped heat insulating casing 51 having an open front side surface, and a heat insulating door 52 is provided to open and close the side opening. A box-shaped first heat conductor 53 is disposed so as to be in close contact with the inner wall of the heat insulating casing 51, and a surface portion of the first heat conductor 53 facing the opening, that is, a substantially central rear side of a back wall portion of the first heat conductor 53. A block-shaped second heat conductor 54 is installed in
A heat transfer medium circulation jacket 56 is in close contact with the rear side of the heat transfer medium via a cascade Peltier element 55. The structure and function of the heat transfer medium circulation jacket 56 are the same as those described with reference to FIG. The air A inside the refrigerator storage room 3 (FIGS. 9 and 1)
0) as indicated by the arrow, along the upper peripheral wall 53a of the first heat conductor 53 to collide with the inner side wall 53b on which the Peltier element 55 is installed, and further descend along the inner side wall 53b. The internal fan 57 and a plurality of heat absorbing fins 58 with guide grooves extending in parallel form the upper peripheral wall 53a.
It is provided inside. Furthermore, the upper peripheral wall 53a
And the thickness of the rear side wall 53 b is slightly larger than the thickness of the other wall of the first heat conductor 53. As described above, if the inside air 57 flows from the upper peripheral wall 53a along the surface of the inner side wall 53b by the function of the internal fan 57 and the heat absorbing fins 58 with guide grooves,
High cooling efficiency can be obtained. In the case of this specific example, the quick freezing room 1 and the thawing room 2
Is used only for freezing or thawing only necessary materials, so that the capacity of both chambers 1 and 2 is relatively small, for example, about 7 liters. In contrast, refrigerated storage room 3 and ice greenhouse 4
Is used for storage and preservation, the capacity of both chambers 3, 4 is relatively large, for example, about 30 liters. Since the capacity of both chambers 3 and 4 is large, and strict control of the temperature in the refrigerator is required to keep the quality of the stored foods and the like constant, as shown in FIG. 3 is provided with a first heat radiating section 59 dedicated thereto, and the ice greenhouse 4 is provided with a third heat radiating section 60 dedicated thereto, so that disturbance is reduced as much as possible. As shown in FIG. 7, the Peltier element 55 is driven by power supply from the element power supply section 61, and the internal fan 57 is driven by power supply from the fan power supply section 62.
The element power supply unit 61 and the fan power supply unit 62 are controlled by a signal from the control unit 63. A temperature sensor 64 is provided on the surface of the first heat conductor 53 near the Peltier element 55, and a detection signal from the temperature sensor 64 is input to the control unit 63. When the heat-insulating door 52 is opened in the refrigerated storage room 3 or when an object to be cooled such as food is put in the refrigerator, the temperature in the refrigerator suddenly rises. , The control unit 6 based on the detection signal.
A large amount of power is supplied to the Peltier element 55 from 3 via the element power supply unit 61. As a result, the temperature of the first heat conductor 53 is rapidly lowered particularly near the Peltier element 55, and tends to be lower than the temperature at which water freezes. The power to the internal fan 57 is increased shortly before the temperature at which the water freezes. As a result, the linear velocity of the internal air A increases, and the thermal conductance at the first heat conductor 53 increases,
The freezing of water on the surface of the first heat conductor 53 is eliminated, so that the humidity in the refrigerator can be kept high. The high-speed rotation of the internal fan 57 may be continuous or intermittent. However, if the high-speed rotation is performed for an excessively long time, electric power is wasted and the storage of vegetables and the like is adversely affected. Must be limited to a level that can maintain the desired value, and then the control mode must be set so that the operation can return to the rated operation. A specific example is as follows. Internal volume: 30 liter insulation material: Two-component non-fluorocarbon foam resin
80 mm thick Peltier element: square with a side of 1.4 mm and thickness 1.
Uses 142 semiconductor chips of 6 mm. Two-stage cascade structure. 6 sets of heat absorption system .............. Equipped with aluminum internal first heat conductor and internal fan and heat absorbing fin.
(Rated voltage 6V) Heat dissipation system ……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… ··································· 30 ° C. In the above-described embodiment, the case of an electric refrigerator in a general home has been described. However, the present invention is not limited to this. For example, a storage box called a home delivery box or the like Applicable to devices. For example, a storage box device is installed in a detached house, condominium, etc., and when a courier visits the recipient's home and is absent, deposit the luggage in the storage box device and send a slip to the recipient's mail box. There is a system for receiving a package in a storage box device, knowing that the package has been delivered when the recipient goes home and is absent from the slip. As the storage box device, for example, the storage device having a refrigeration or freezing function for storing living things such as meat and fish can be applied to the storage device of the present invention. As described above, the present invention is restricted to a range of 1.3 to 2 times the steady-state power required to maintain the set temperature in the refrigerator with the heat-insulating door closed. The power is supplied to the Peltier device from the device power supply unit. In this way, as described above, even if the heat-insulating door is opened and closed, it can be cooled to the set temperature in a short time and economically.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a temperature characteristic diagram showing a set temperature in a refrigerator and a temperature change in the refrigerator when a door is opened and closed. FIG. 2 is a temperature characteristic diagram showing a set temperature in a refrigerator and a temperature change in the refrigerator when a door is opened and closed. FIG. 3 is a temperature characteristic diagram showing a set temperature in a refrigerator and a temperature change in the refrigerator when a door is opened and closed. FIG. 4 is a characteristic diagram showing a relationship between a current supplied to a Peltier element and a heat absorption amount. FIG. 5 is a characteristic diagram showing a relationship between electric power supplied to a Peltier element and a temperature in a refrigerator. FIG. 6 is a characteristic diagram showing a relationship between input power / stationary power and a return time to a set temperature. FIG. 7 is a front view of the combination device according to the embodiment of the present invention. FIG. 8 is a plan view of the combination device. FIG. 9 is a cut-away side view of the combination device. FIG. 10 is a plan view of a refrigeration storage room and an ice greenhouse that constitute a part of the combination device. FIG. 11 is a partially enlarged perspective view of a cable storage case used for the combination device. FIG. 12 is an enlarged sectional view of a heat transfer medium circulation jacket used for the combination device. FIG. 13 is a diagram showing characteristic patterns of temperature control of a compressor-type refrigerator and temperature control of a refrigerator using a Peltier element. DESCRIPTION OF SYMBOLS 51 Insulated casing 52 Insulated door 53 First heat conductor 54 Second heat conductor 55 Cascade Peltier element 56 Heat transfer medium circulation jacket 57 Internal fan 58 Heat absorption fin 59 First heat radiating section 60 Third heat radiating section 61 Element Power supply unit 62 Fan power supply unit 63 Control unit 64 Temperature sensor A Inside air

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Katsuhiro Tono 1-7-7 Shiohama, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Inside Thermobonic Co., Ltd. (56) References JP-A-6-207771 (JP, A) 62-120172 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25D 11/00 F25B 21/02

Claims (1)

(57) [Claims 1] A casing formed of a heat insulating layer, a heat insulating door for opening and closing an opening of the casing, A heat conductor having an opposing heat transfer surface, a Peltier element thermally in communication with the heat conductor, and an element power supply unit for supplying power to the Peltier element, and within 12 minutes after opening and closing the heat insulating door. Cool down to the set temperature in the refrigerator
In order to maintain the in- compartment set temperature of the casing in a state in which the heat-insulating door is closed at 30 ° C. in outside air , power regulated to a range of 1.3 to 2 times the steady power required for maintaining
An electric refrigerator configured to be supplied to the Peltier device from the device power supply unit.